1. Field of the Invention
The present invention concerns an oil-soluble N-long chained acyl acidic amino acid ester having at least one sterol ester, an oily composition consisting of or comprising a mixture of such esters, as well as cosmetics and external preparations prepared by blending such ester or such oily composition.
2. Description of the Prior Art
Various kinds of esters have generally been used as oleo-phase materials for skin and hair cosmetics and medicines for external application. Further, amino acid type surface active agents of natural origin and with high safety have often been used recently. By the way, most of such amino acid type surface active agents are hydrophilic and, as oil-soluble amino acid type surface active agent usable as the oleo-phase material for cosmetics, etc., N-lower acyl acidic amino acid diesters, N-long chained acyl acidic amino acid diesters, N-long chained acyl neutral amino acid ester and N,N-di-long chained acyl basic amino acid esters and the like have been known.
However, although the known compounds as described above have some degree of emulsifying and hydrating performances, both of the performances are remarkably low in the N-long chained acyl acidic amino acid higher alcohol diesters, and more excellent high performances are required for the improvement of the performance, for example, of cosmetics.
On the other hand, various kinds of sterol esters have hitherto been used as the oleo-phase material having the excellent emulsifying performance and further of excellent moisture permeability because of its melting point of 35.degree..about.40.degree. C. near the body temperature. Excellent moisture permeability prevents the skin blocking caused by cosmetics. They have particularly preferred hydrating performance but involve a drawback that the use of products gives somewhat heavy feeling when they are blended with cosmetics.